Privacy: Encrypted Email

Criteria ProtonMail Skiff Tutanota
Audited? Yes Results not released Web client only
Available on Debian? Paid Bridge Only Website only Yes
Available on Mac? Paid Bridge Only Yes Yes
Available on Windows? Paid Bridge Only Website only Yes
Available on Android? Yes Yes Yes
Available in F-Droid (Android Only)? No No Yes
Available on iOS? Yes Yes Yes
Based in 5/9/14 Eyes? No Yes Yes
Free plan available? Yes Yes Yes
PGP support Yes No No
Backup/Export available Yes Import only Export only
Additional notes? Includes VPN service, Calendar, and Drive storage with all plans Includes collaborative workspace and Drive storage with all plans Includes Calendar with all plans